A. Field of the Invention
The invention relates to the field of wireless networks in which a large number of nodes communicate with a central computer. The invention relates more particularly to avoiding jamming in such a system.
B. Related Art
The aforementioned related applications describe The application relates to packet hopping networks in which messages are communicated wirelessly from a central computer to a network of nodes. The central computer has a weak transmitter and does not have the ability to communicate with all of the nodes. Accordingly, various nodes act as re-transmitters for retransmitting information to the others. Such networks are particularly useful for lighting control in a building.
In U.S. application Ser. No. 08/498,286, jamming was avoided by having a transmitting node slide its transmitting frequency with a relatively slow slide frequency. A receiving node would then slide its receiving frequency relatively quickly, to scan for transmitters. The receiving node would then temporarily freeze its receiving frequency upon crossing the frequency used by the transmitter. The receiver could then receive the message intended for it. Since transmission takes place at different frequencies, chances of being stuck at a frequency which is jammed was unlikely.